Commits

Introduced XmppWsgiServerInterface class which should be used to implementinterface to additional XMPP libraries and to allow XmppWsgiServer communicatewith them.

Also this tricks helps(should) with testing due to we could easily be abstractedfrom any XMPP realisaion (see MockXmppWsgiServerInterface) and wouldn't bindXMPP library and XmppFlask app.

Additionaly, XmppWsgiServer environ has extended by new variables: - APP_JID: XmppFlask app bounded full JID. App should know his own JID. - APP_MUCNICK: XmppFlask app MUC nick if message type is groupchat. - XMPP_ID: XMPP stanza id. If not specified by income event, it would be created by using 'xmppflask' as prefix and uuid1 first 8 bytes as suffix. - XMPP_DELAY: Shows delay in seconds between current UTC time and point when income event was occurred.